In the past, switching process (network selection or and traffic steering) has been proposed. In a case where at least one part of a coverage area of a mobile communication network as represented by LTE (Long Term Evolution) and a coverage area of a wireless LAN are overlapped, the switching process switches a standby destination or a connection destination between the mobile communication network and the wireless LAN. To be more specific, a radio terminal performs the switching process on whether first information of the mobile communication network satisfies a first condition and whether second information of the wireless LAN satisfies a second condition.
Here, the first information of the mobile communication network includes a measurement result (RSRPmeas) of signal level of received signal (RSRP; Reference Signal Received Power) and a measurement result (RSRQmeas) of signal quality of received signal (RSRQ; Reference Signal Received Quality), for example. The second information of the wireless LAN includes a channel utilization value of the wireless LAN, a backhaul value of the wireless LAN, and a signal strength of received signal (RSSI; Received Signal Strength Indicator), for example.
Meanwhile, determination parameters are notified from a base station included in the mobile communication network to a radio terminal. The determination parameters are used for the radio terminal to determine whether to switch a standby destination or a connection destination between the mobile communication network and the wireless LAN. There are dedicated parameters notified to each radio terminal individually and broadcast parameters broadcasted to radio terminals, as the determination parameters.